serpent
The meaning of the serpent is attachment to the human world.
(‘Abdu’l-Bahá,
Some Answered Questions,
page 123)
spirit and soul
Adam signifies the heavenly spirit of Adam, and Eve His human soul.
(‘Abdu’l-Bahá,
Some Answered Questions,
page 123)
symbolical
Therefore, this story of Adam and Eve who ate from the tree, and their expulsion from Paradise, must be thought of simply as a symbol. It contains divine mysteries and universal meanings, and it is capable of marvelous explanations.
(‘Abdu’l-Bahá,
Some Answered Questions,
page 123)
tree of good and evil
The tree of good and evil signifies the human world; for the spiritual and divine world is purely good and absolutely luminous, but in the human world light and darkness, good and evil, exist as opposite conditions.
(‘Abdu’l-Bahá,
Some Answered Questions,
page 123)
tree of life
The tree of life is the highest degree of the world of existence: the position of the Word of God, and the supreme Manifestation.
(‘Abdu’l-Bahá,
Some Answered Questions,
page 124)
This tree of life was the position of the Reality of Christ; through His manifestation it was planted and adorned with everlasting fruit
(‘Abdu’l-Bahá,
Some Answered Questions,
page 124)
Sin is the state of man in the world of the baser nature, for in nature exist defects such as injustice, tyranny, hatred, hostility, strife: these are characteristics of the lower plane of nature. These are the sins of the world, the fruits of the tree from which Adam did eat.